The energy management of multi-room, or multi-suite, facilities such as hotels, apartment buildings, office complexes, dormitories, office buildings, classrooms, cruise ships, laboratory facilities, and similar structures is complex and demanding. Specifically, the unique demands associated with multi-room facilities, including facility security, facility operational efficiency, and facility maintenance, can contribute to high operational costs for the typical facility operator. As multi-room facilities increase in size so do the costs associated with facility management and maintenance.
In a hotel, for example, individual rooms utilize devices/elements such as doors, electronic locks, Do Not Disturb (DND) devices, lights, heating, ventilation, and air conditioning (HVAC), safe, minibar, draperies, maid communication devices, room occupancy detection and communication, and more and all have a potentially high impact on the hotel operation (particularly the operating costs) as well as guest comfort.
Many building owners, including the owners of apartments, offices and hotels, continue to seek methods to decrease their HVAC expenses. One method to do so is to select minimum and maximum setback temperatures for a room, which require less operation of the room's HVAC equipment, when the room is not occupied. This method requires an accurate occupancy sensor.
In the past, motion detectors have been used as occupancy sensors in rooms. In particular, infrared motion detectors have been used. An infrared motion detector typically measures persons or objects that are both 1) showing a selected surface temperature difference from that of the room and 2) moving at a selected speed.
However, the use of a motion detector as an occupancy sensor does not produce an accurate indication of a room being occupied in situations in which an occupant remains motionless for an extended period of time, such as in sleeping, reading or watching television. The motion detector is also not accurate in rooms in which the geometry of the room includes blind spots to the motion detector such as alcoves or bathrooms.
Moreover, the use of motion detectors may be capable of differentiating between a general state of occupancy associated with a room, but they are incapable of determining a general or specific location of the occupant after the occupant has left the room. As such, the typical multi-room facility operator cannot make use of more efficient energy management techniques and deeper setback controls to save the wasted energy consumption costs associated with an unoccupied room.